/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
 *  with the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing,
 *  software distributed under the License is distributed on an
 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 *  KIND, either express or implied.  See the License for the
 *  specific language governing permissions and limitations
 *  under the License.
 */
package groovy.lang;

import java.util.EventListener;

/**
 * A listener called whenever a constant MetaClass is set, removed or replaced.
 *
 * @see groovy.lang.MetaClassRegistry
 * @see groovy.lang.MetaClassRegistryChangeEvent
 *
 */
public interface MetaClassRegistryChangeEventListener extends EventListener{

    /**
     * Called when the constant MetaClass is updated. If the new MetaClass is null, then the MetaClass
     * is removed. Be careful, while this method is executed other updates may happen. If you want this
     * method thread safe, you have to take care of that by yourself.
     *
     * @param cmcu - the change event
     */
    void updateConstantMetaClass(MetaClassRegistryChangeEvent cmcu);
}
